1. Field of the Invention
The invention relates to a device for separating prefolded, foldable sheet pieces, in particular letter envelopes with flaps.
2. Brief Description on the Background of the
Invention Including Prior Art
Separator devices for letter envelopes are known in postage metering machines such as, for example, described in Hasler Review, Vol 11, 1978, Issue No. 1, pp 1-7. In such devices the letter envelopes are placed with flaps closed as a stack on a support as shown in FIG. 3 of the reference above. In each case, the lowest envelope is pulled away in longitudinal direction and fed to the postage metering section by a feed device, for example, rollers with a good gripping surface (Compare FIG. 1 of the reference). According to this procedure, the flap can in each case be open to some extent, can be moistened, can be reclosed and can be adhesively attached under pressure (Compare the sections 2.3.2 and 2.3.3 on page 7 of the above reference).
Furthermore, postage metering machines are known where the stack of letter envelopes can be inserted with the flaps open at an about right angle. Because of the thickness of the paper, stampings at an angle result because of the manner of stacking. The stacks have to be maintained at their side in order to provide a sufficiently accurate positioning for the stack. Furthermore, a slot has to be located between the side wall and the support of the stack in each case, and the flaps of the envelopes drop down into the slot.
Because of the slot however, an exact side guide is only provided to a limited extent such that the position at which the postage stamp is placed on the envelope is subject to variations. Furthermore, it easily occurs that envelopes are stamped at an angle, which is not permissible in the case of high quality requirements.